January 30, 2014 at 1:00 am

Detroit researchers look at causes of premature births

Research leads to screening for premature birth ri...
Research leads to screening for premature birth ri...: Dr. Roberto Romero of Detroit's Hutzel Women's Hospital discusses new practices to help avoid premature births, a key factor in Detroit's high infant mortality rate.

Groundbreaking discoveries by researchers at the Detroit Medical Center are helping explain why so many Detroit babies are born too early, and could position the city to lead global efforts to prevent prematurity and save babies’ lives.

So many babies die in Detroit that the National Institute on Child Health and Human Development, in collaboration with Wayne State University, located its Perinatology Research Branch at the Detroit Medical Center in 2002. Its mission is to discover why some pregnancies don’t go well, and to find tests to predict preterm births and treatments to prevent them.

The primary cause of infant mortality, in Detroit and elsewhere, is preterm birth — babies born too soon to survive. A baby born at “term” is delivered between 38 and 41 weeks of gestation; most are born at 40.

According to Dr. Roberto Romero, chief of the Perinatology Research Branch, about two-thirds of preterm births happen because the mother spontaneously goes into labor. The other third occur when health conditions, such as a woman’s high blood pressure or the fetus’ failure to grow, require doctors to deliver the baby early by Caesarian section.

Women have a greater chance of preterm birth if they have a short cervix, the narrow passage at the base of the uterus through which the baby passes during birth. According to Romero, women who are shown by ultrasound, taken between 19 and 24 weeks of pregnancy, to have a cervix that is shorter than 25 mm, have a 70 percent greater risk of delivering their babies at less than 33 weeks of gestation.

But research conducted in Detroit has uncovered a promising treatment for women with short cervixes.

In a study that spanned 44 countries, Romero and Wayne State University Associate Dean Dr. Sonia S. Hassan, director of advanced obstetrical care and research with the Perinatology Research Branch, found that vaginal progesterone can significantly reduce the risk of early labor in women diagnosed with short cervixes.

Daily use of vaginal progesterone gel reduced by 45 percent the number of preterm births that occurred before 33 weeks among study participants with short cervixes. Preterm deliveries between 28 and 33 weeks of gestation were reduced by about half, and those between 28 and 38 weeks were reduced by more than a third.

The medicine also significantly reduced the number of babies born to such women with lungs that weren’t fully developed. The study found a 61 percent reduction in the rate of respiratory distress syndrome — meaning babies were born with lungs too immature to breathe on their own — among infants whose mothers used the vaginal progesterone gel.

“Progesterone prevents early preterm deliveries, which are the ones for which there is the greatest (risks for babies) in terms of complications for the long term,” Romero said.

The global study also revealed that more Detroit women suffer from the condition of short cervix than women in other parts of the country or the world.

“The rate of short cervix in Detroit was almost 6 percent, and 2 percent in other regions,” said Hassan. “It can be one explanation of why the rate of preterm birth is high.”

Researchers are looking into whether short cervix is more common among African-American women, who are known to have higher rates of preterm births, Hassan added. Detroit has the largest percentage of African-Americans of any major U.S. city. In 2010, the last year for which comprehensive data was available from the U.S. Census Bureau, 87.2 percent of the city’s population was African-American.

Another cause of preterm birth discovered at the DMC is Fetal Inflammatory Response Syndrome, caused when bacteria that exist in the vaginas of all pregnant women migrate into the uterus and infect the amniotic fluid that the fetus breathes in the womb. A study authored by Hassan found a link between this condition, also called intra-amniotic infection, and short cervix.

In other research, doctors from Wayne State University, the Perinatal Research Branch and the DMC have discovered a way to detect congenital heart defects in fetuses, one of the most common causes of infant mortality. They also have devised a method to predict when a baby may be stillborn, allowing time for medical interventions.

Researchers have linked late preterm deliveries, those that occur at about 34 or 35 weeks of gestation, to a physiological rejection of the fetus that may be caused by chronic stress in the mother, such as depression — an important discovery since babies born preterm after 34 weeks of gestation face higher risks of cerebral palsy and other serious health problems.

“If you’re asking me what can we do here in Detroit to reduce preterm delivery, universal cervical length screening and progesterone is one of the interventions we can institute immediately,” Romero said. “Generally it takes several years for a discovery to be implemented into general practice, (but) given that this was a discovery that was made here in Detroit, I think that we are ideally poised to implement that into clinical practice.

“We don’t have to go and learn how to do that from people who are in other parts of the country because the people are right here. I believe that is a hopeful message.”

Dr. Roberto Romero, director of the Perinatology Research Branch of the National Institutes of Health at the Detroit Medical Center. / Photos by Max Ortiz / The Detroit News
Dr. Sonia Hassan, director of research at Perinatology Research Branch, ... (Max Ortiz / The Detroit News)